Bulk material processing plants or machines can be static or transportable between operational sites. In some instances, the processing machines are transportable to be assembled or configured for use in situ or may be self-propelled to be easily manoeuvred on site and to facilitate loading and unloading at a platform of a transport vehicle.
Example processing plants include screeners, crushers and combined crushing and screening apparatus. These machines typically include a loading hopper which receives a supply of bulk material that is then fed to a screen box or a crusher for subsequent discharge via one or a number of intermediate or discharge conveyors. The supply from the hopper to the primary or secondary processing units (screen or crusher) typically relies on gravity discharge such that the screen or crusher is generally positioned lower than the input hopper that typically determines the maximum height of the processing plant and is the uppermost component. Accordingly, it is known to configure the hopper with walls that are capable of falling or collapsing downwardly to appreciably reduce the overall machine height and allow convenient transport along public highways without risk of impact with overhead obstructions such as bridges and the like. Example foldable hopper arrangements are described in US 2004/0035963; US 2006/0016104; US 2008/0041984; EP 2664492; GB 2496522 and US 2014/0124337.
However, conventional adjustably mounted hoppers are disadvantageous for a number of reasons. In particular, service personnel are often required to physically climb the plant to manually manipulate locking components at the hopper walls. As will be appreciated, in use, the walls must be secured reliably to withstand the significant loading forces that are imparted to the walls as the hopper is supplied with bulk material. Additionally, it is not uncommon for power operated actuators to become worn over time or to fail and this represents a significant safety risk to personnel where the hopper wall locking mechanism relies or is dependent upon the integrity of electronic or fluid based actuators. Accordingly, what is required is a hopper arrangement that addresses these problems.